MsExchange Blog Spot Telnet25

January 29, 2013

Exchange 2010 & 2013 Active Passive Database IOPS

Filed under: General — telnet25 @ 7:20 pm

This is one of the most frequent asked topic, and misunderstood concept in my opinion. When it comes to design and giving decisions on how to architect your environment , you need to realize the

IOPS you will get from your active and passive DB copy in Exchange 201 are the same ( almost). The misconception is the passive DB should not be required such IOPS as no user activity is expected on the passive copy and this assumption turns out not to be true. Perhaps the very aggressive pre-reading Exchanged 2010 does to maintain the passive DB integrity and low check point for fast fail over design in Exchange 2010 architecture contributes the “fact”.

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In Exchange 2013 where does this falls into ? the passive copy IOPS are reduced %50 percent, Exchange 2013 is offering huge IOPS reduction over Exchange 2010. The aggressive pre-reading is no longer being done within the passive copy, due to changes have been done to ESE logging.

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Exchange 2013 is looking real promising, Although the product is not fully ready IMO , “yet” once pieces put together and given little time I am pretty sure it will offer some compelling business reasons to move into Exchange 2013 version.

Resource

http://blogs.technet.com/b/scottschnoll/archive/2012/09/19/storage-high-availability-and-site-resilience-in-exchange-server-2013-part-1.aspx

Respectfully,
Oz Casey, Dedeal ( MVP north America)
MCITP (EMA), MCITP (SA)
MCSE 2003, M+, S+, MCDST
Security+, Project +, Server +
http://smtp25.blogspot.com/ (Blog)
https://telnet25.wordpress.com/ (Blog)

January 9, 2013

Exchange 2010 CAS Server Scalability and Limitations

Filed under: General — telnet25 @ 5:12 pm

I have asked recently this question , one of our costumer wanted to know what the CAS server limitations were in Exchange 2010. As the questions sounds broad to be more specific the client wanted to know how many  OWA users could continue to use the services if worst happens , in the scenario we end up losing such number of CAS 2010 Servers. Good question to be honest and here is pretty much all you need to know to get the bottom of this question.

First of all in the scenario of giving design decision, what makes the most sense? how many servers do we need for giving scenario ? Million thanks to Exchange team,  use the Calculator, it will tell you what you need and most of the leg work is being done by the calculator itself.

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Calculator

http://blogs.technet.com/b/exchange/archive/2009/11/09/3408737.aspx

Now, should you be combining roles or not? It all depends in general , as good practice the simpler design is the “Best one” keep this in mind. So this being said, most engineers have been combining at least HTS/CAS roles anyways.

Should combine MBX role as well? the answer is depends and depends but same rule applies, “ keep it simple” it really is not a brainer, if you are going to architect messaging solution for 100K users , ask yourself how may DAGS you will need ? Take a look at business model (how they are operation in current) and its logical segregation use that to align your design solution and remember the DG boundaries are 16 Servers.

Now you are going to deploy 2 DAGs and each DAG will have 10 Servers in total you end up having 20 MBX Servers. Remember the Exchange calculator will do the hard work for you and how many combined roles servers (HTS & CAS ) you would need ? to accommodate this design ? The answer is going to be , 1 to 1 ratio ( simple isn’t it ) so

E2013 Data Loss Prevention Steve Chew

Option 1 = 60 Servers

HTS Servers

20 HTS Servers

Combined Servers ( CAS & HTS )

20 CAS Servers

DAG1 ( MBX )

10 MBX Servers

DG 2 ( MBX )

10 MBX Servers

Option 2 = 40 Servers

Combined Servers ( HTS & CAS )

20 CAS Servers

DAG1 ( MBX )

10 MBX Servers

DG 2 ( MBX )

10 MBX Servers

Option 3 = 20 Server

Multi Role Configuration

20 ( HTS & CAS & MBX )

DAG1

10 ( HTS & CAS & MBX )

DG 2

10 ( HTS & CAS & MBX )

Now remember the golden rule keep it simple, the “simple deployment” is the best one so use your logic and common sense to decide which one of these makes the most sense? You have to evaluate your own specific requirements as this fluctuates per given scenario and costumer.

Same story goes for choosing the platform, should we take advantage from virtualization technologies or deploy hardware solutions? I personally favor the virtualization deployments fir reasons I have talked about on my previous blog post.

Exchange 2010 Virtualization and Combining Server Roles?

http://smtp25.blogspot.com/2013/01/exchange-2010-virtualization-and.html

Finally Exchange 2010 CAS limits? How many OWA connections a single E 2010 CAS server can support up to? In the scenario the E 2010 CAS Server is running on top of Windows 2008 R2? The issue we will talk about is not the application limitations but remember there is no application called “limitless” there will be a point when things won’t work the way they should be. (Response time, Client end user experience etc.)

Plan your server provisioning steps and document is incase “bad” happens, this way you will know how long it will take to bring another CAS server into existing CAS ARRAY , remember once the infrastructure is set correctly adding CAS servers into existing CAS pool behind the HLB is simple work and it should be seamless to your end-users. Plan your Change control process, procurement etc. (this is why Virtual infrastructure makes a lot of sense, easy and fast server deployment.)

Each Client connection is made up of source IP Address, Source Port & Destination IP and destination port (The TCP/IP basic) as long as CAS Server does have additional IP Address , the CAS server can scale 60K outbound connections per source IP address

A CAS server is not limited to 60000 TCP connections. It is limited to 60000 unique combinations of source IP, source port, destination IP, and destination port for each IP defined on the CAS server.

This means that a CAS server with a single IP address can support more than 60000 TCP connections at the least. Remember there will be CPU and Memory issues when so many connections start hitting the single CAS Server, and this is exactly why you need to plan your infrastructure and make sure in a bad scenario the services are going to be provided to end users.

Resources

Calculator

http://blogs.technet.com/b/exchange/archive/2009/11/09/3408737.aspx

Exchange Scale Limitations Spreadsheet

http://gallery.technet.microsoft.com/exchange/Exchange-Scale-Limitations-34306f77

Respectfully,
Oz Casey, Dedeal ( MVP north America)
MCITP (EMA), MCITP (SA)
MCSE 2003, M+, S+, MCDST
Security+, Project +, Server +
http://smtp25.blogspot.com/ (Blog)
https://telnet25.wordpress.com/ (Blog)

January 2, 2013

Exchange 2010 Virtualization or NOT

Filed under: General — telnet25 @ 4:53 pm

One of the most frequent asked question around design and deployment scenarios , should business go for virtualization when it comes to deploying Exchange 2010 and newest versions. This has almost be the hot topic to be honest and I wanted to highlight some of the bullet point to help for those who need to give the similar decisions on your deployment project.

Before we deep dive into Virtualization we need to be clear about combined roles in Exchange 2010 deployment and talk about it how much it make sense ?

One of the most significant difference in between Exchange 2010 and 2013 is the simplicity, and doing things in easy and more efficient way. The server roles reduction in Exchange 2013 is one of the example, so let’s take a quick look server roles so we do understand and give better decision on combining server roles.

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Reduced Server Roles

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I am personally favoring to go for Virtualization when it is possible and makes sense for the business and here are some of the compelling reasons why I think the Virtualization is the way to go.

The Exchange server application is more and more focusing about the idea of simplicity, getting things done in simple way while providing better services and of course this statement will expand from server perspective to end user experience.

Virtualization Benefits ( Exchange 2010 and 2013)

  • Reduced server hardware costs
  • Power and space saving
  • Improved server utilization
  • Fast Server provisioning
  • Under-utilized hardware, and can reduce hardware and maintenance costs
  • Virtualization provides organizations additional choice and deployment flexibility to meet business requirements and lower IT costs and complexity
  • Combining Roles does it make sense?

The answer IMO to this is real short and yes, if you ever design any environment you will quickly see the reduction on the server numbers once they are combined, Remember the most reason ratio for CAS and MBX server, one to one. So if you have 10MBX Server you will need 10 CAS Servers and most probably you will combine CAS & HTS Servers , this is what most people have been doing since Exchange 2007.

Now imagine if you combine HTS, CAS and MBX roles the server count in the same example reduces 50 percent and this is why I am all for combining roles which makes the most sense.

Microsoft Official Stand for Virtualization

Does Microsoft support combining roles and Virtualizing Exchange 2010 servers ? The answer is yes , see below official support statement from MSExchange Team.

http://blogs.technet.com/b/exchange/archive/2011/05/16/announcing-enhanced-hardware-virtualization-support-for-exchange-2010.aspx

  • Hypervisor-based clustering, high availability, or migration solutions that will move or automatically failover mailbox servers that are members of a DAG between clustered root servers, is now supported.
  • The Unified Messaging server role is supported in a virtualized environment.
  • Combining Exchange 2010 high availability solutions (database availability groups (DAGs)) with hypervisor-based clustering, high availability, or migration solutions that will move or automatically failover mailbox servers that are members of a DAG between clustered root servers, is now supported.

When Exchange Server roles are combined there will be additional administrative overhead managing Exchange Servers and also few things to take into considerations

  • HUB transport Server and mail submission Service default behavior
  • DAG implementation, FSW Consideration in DAG
  • Multi Role deployment Server patching overhead and recommendations

Here is more comprehensive Information.

Conclusion: As you can see from this short post , there are good enough reasons, why to start with multi role deployment and take advantage of Virtualization technologies when deploying Exchange 2010 and 2013 versions.Remember the more simple design is the “best” design in most of the cases. Exchange 2013 has many futures simplifies such deployment and brings on a table huge IOPS reduction. Here is projected IOPS comparison.

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Respectfully,
Oz Casey, Dedeal ( MVP north America)
MCITP (EMA), MCITP (SA)
MCSE 2003, M+, S+, MCDST
Security+, Project +, Server +
http://smtp25.blogspot.com/ (Blog)
https://telnet25.wordpress.com/ (Blog)

 

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